Apparatus for and method of adjusting location of shaft bearings on grate conveyor

ABSTRACT

An apparatus for and a method of adjusting the location of the shaft bearings, particularly the tail shaft bearings, on a grate conveyor or the like, to maintain proper tension on the chains of the conveyor to compensate for change in length of the chains due to temperature change and wear, while also insuring parallelism of the head and tail shafts of the conveyor with respect to each other. Each shaft bearing whose position is to be adjusted is supported on a slidably adjustable mounting means, and a fluid motor such as a hydraulic ram is mounted with the cylinder thereof in a fixed position on the shaft support structure for a given range of adjustment of the bearing, the ram being pressurized to move the slidable mounting means and the bearing carried thereby to an adjusted position. Precisely dimensioned shims are interposed between the cylinder of the hydraulic ram and the adjustable mounting means to maintain the bearing in a given adjusted position, and after the shims have been so interposed the hydraulic ram is depressurized but the ram cylinder remains in its fixed position to serve as an abutment for the shims.

United States Patent [191 Hartwig Oct. 16, 1973 APPARATUS FOR AND METHODOF [57] ABSTRACT ADJUSTING LOCATION OF SHAFT An apparatus for and amethod of adjusting the loca- BEARINGS 0N GRATE CONVEYOR tion of theshaft bearings, particularly the tail shaft [75] Inventor: Walter J.Hal-twig, ()c n w bearings, on a grate conveyor or the like, to maintainWis. proper tension on the chains of the conveyor to compensate forchange in length of the chains due to tem- [73] Assgnee:Alps'chalmersporporaflon perature change and wear, while also insuringparallel- Mflwaukee ism of the head and tail shafts of the conveyor withre- [22] Filed: June 6, 1972 spect to each other.

[21] APPL 260,129 Each shaft bearing whose position is to be adjusted issupported on a slidably adjustable mounting means, and a fluid motorsuch as a hydraulic ram is mounted UeS. Cl. R the cylinder thereof in afixed position on Int Cl. shaft upport structure for a given range ofadjustment of Search u n of the bearing the ram being pressurized tomove the 74/242-14 R; 254/93 R3 92/15 23; 432/121 slidable mountingmeans and the bearing carried thereby to an adjusted position. Preciselydimensioned [56] References Cited shims are interposed between thecylinder of the UNITED STATES PATENTS hydraulic ram and the adjustablemounting means to 2,797,075 6/1957 Wilbur 198/208 x maintain the bearingin a given adjusted position, and

3,155,555 6/1964 Caskey 92/23 x after the Shims have been so p ed e y auic 3,568,569 3/1971 Haley 74/242.l4 R X ram is depressurized but the ramcylinder remains in its fixed position to serve as an abutment for thePrimary Examiner-Edward A. Sroka shims.

Attorney-Robert C. Sullivan et a]. g

20 Claims, 7 Drawing Figures 2 l6 9 B A woo p o g o go PATENIEBucI 16 m53.765.525

sum 10F 2 APPARATUS FOR AND METHOD OF ADJUSTING LOCATION OF SHAFTBEARINGS ON GRATE CONVEYOR BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to traveling grates for use inGrate-Kiln systems or the like such as those used in the heat processingof pelletized mineral ore or the like, and more particularly toapparatus for and a method of adjusting the position of the shaftbearings, such as the tail shaft bearings, for such a traveling grateconveyor in order to maintain proper tension on the drive chains of thegrate conveyor, and thus maintain proper tension on the conveyor.

2. Description of the Prior Art In the prior art practice, travelinggrates for use in Grate-Kiln systems or the like have been field alignedto provide upon initial set-up a true rectangular relation of the headshaft and of the tail shaft bearings with respect to each other. Thehead and tail shafts carry sprockets about which the conveyor drivechains on either lateral side of the conveyor, and, in some cases,intermediate the transverse width of the conveyor, pass. It is importantto have a true rectangular relation of the head and tail shafts and ofthe bearings therefor whereby to insure parallelism of the head shaftand of the tail shaft relative to each other, since any departure fromparallelism of these two shafts will cause the conveyor chains and hencethe conveyor grates carried thereby to drift or run toward either sideof the conveyor, thereby presenting serious operating problems. If theparallel relation of the head and tail shafts and the correspondingrectangular arrangement of the supporting bearings of these two shaftsis disturbed, the grate conveyor must be shut down for resurvey andrealignment.

Two important factors cause a change in the length of the conveyor chainduring the operation of the conveyor as compared to the original lengthof the chain at the time of start-up of the conveyor, as follows:

1. Increase i n chain length dueto operating temperature. Assume apitches, each link having a 10 inch pitch, for a conveyor having a totallength of 4,000 inches. If the average chain operating temperature is500 F then it can be shown in'this assumed hypothetical case that a 12inch length increase of chain results from the increase in operatingtemperature from the cold shut-down temperature to the assumed operatingtemperature of 500 F. (4,000 X 5,000 X 0.000006 12 inches), where0.000006 is the assumed temperature coefficient of expansion of thechain. Such a 12 inch increase in chain length would require a 6 inchadjustment of the head or tail shaft to compensate for chain elongation.In the prior art, this 12 inch of increased chain length due totemperature increase from cold shut-down to operating temperature as setforth in-the example just given was tolerated and nothing was done toadjust the location of the shaft bearings to compensate for thistemperature-caused increase in chain length. This increase in chainlength due to the temperature rise to the operating temperature from acold shut-down normally occurs in a relatively short time such as afterabout 24 hours of operation. 2. Increase in chain length due to wear. Asecond and more important factor in causing an increase in chain lengthis the wear which occurs at conveyor chain having l links 6;

the chain pin and chain link connection which causes a normal pitchincrease of about inch per pitch per year. Thus, in the preceedingexample, if the chain has a total length of about 400 pitches or links,then the length increase per year of the chain due to wear on theaverage would be inch X 400 50 inches total increase in chain length peryear. This increase would require an adjustment of the head or tailshaft of about 25 inches to maintain the chain tension as it was when itwas cold installed. This 25 inch adjustment of the head or tail shaftjust mentioned is only to compensate for the wear of the chain and, aspreviously described, an additional adjustment for temperature-causedchain elongation is also necessary.

There are a number of disadvantages due to the lack of tension andresultant looseness in the chain and in the conveyor produced by theincreased chain length as just described. This increased length due toeither of the causes previously described (i.e., temperature and wear)is usually accumulated as catenaries between the return rollers of theconveyor, which results in hesitation of the return run of the conveyorand slackening of the conveyor chain in the loading zone, causing minorcatenaries of chain undulation on the upper run of the conveyor at thefeed end of the conveyor. The chain undulations and consequent similarundulations of the conveyor supported by the chain is comparable tohills and valleys. In the valleys, the green pellets of the pelletizedore or the like compact, while in going over the hills or crestsproduced by the foregoing described undulations, the pellet bed opensup, resulting in pellet degradation. Wet pellets tend to compact ordeform in the valleys", while the pelletload passing over the crests orhills tend to form craters, cracks, or to open up. This undulation whenpassing through the drying furnaces forms preferential air flow channelswhich are detrimental to an ideal process condition. It can be seen thatthe problem of slack chain produces process conditions which tend toseriously reduce the quality of the product and to produce lack ofuniform quality of the product.

In accordance with the practice of the prior art it was the generalpractice to tolerate and ignore the change in chain length due totemperature increase. With respect to the change in chain length causedby wear it has been the practice in the grate conveyor prior art to shutdown the conveyor at the end of a predetermined period such as threemonths and to remove sufficient chain links from the chain to restorethe chain to substantially its original tension. In removing chain linksas just described, it was also necessary to remove corresponding gratesfrom the grate conveyor.

In many installations of traveling grates for pelletized ore plants itis desired that the traveling grate run steadily for periods of 6 to 9months or even for one year without shutdown. It can be seen that theexcess chain length produced by the factors previously described makedifficult the fulfillment of this objective of steady operation of theconveyor for 6 months to one year, the excess chain frequently forcing ashut-down of the plants for readjustment of the chain after shorterperiods of operation such as 3 months.

STATEMENT OF THE INVENTION Accordingly, it is an object of the presentinvention to provide an apparatus for and a method of adjusting theposition of a shaft of a traveling grate conveyor whereby to maintainproper tension on the traveling grate and the chains thereof.

It is another object of the invention to provide an apparatus for and amethod of adjusting the position of the shaft of a traveling grateconveyor which permits adjustment of the tension of the conveyor chainswhile the traveling grate is in operation.

It is a further object of the invention to provide an apparatus for anda method of adjusting the position of a shaft such as the tail shaft ofa grate conveyor which insures the maintenance of true parallelism ofthe head shaft and of the tail shaft of the traveling grate with respectto each other.

It is a further object of the invention to provide an apparatus for anda method of adjusting the tension of a grate conveyor and the chainsthereof to compensate for dimensional changes caused by temperature andby wear on the conveyor chain.

It is a still further object of the invention to provide an apparatusfor and a method of adjusting the tension of the chains of a travelinggrate conveyor, whereby to insure a uniform high quality processing ofthe ore pellet load or the like carried by the grate conveyor.

It is still a further object of the invention to provide an apparatusfor and a method of adjusting the tension of the chains of a travelinggrate conveyor which provides increased operating time of the conveyor,due to reduced maintenance time required, and which also providesreduced maintenance cost, and increased chain life.

In achievement of these objectives, there is provided in accordance withan embodiment of the invention as apparatus for and a method ofadjusting the location of the shaft bearings, particularly the tailshaft bearings, on a grate conveyor or the like, to maintain propertension on the chains of the conveyor to compensate for change in lengthof the chains due to temperature change and wear, while also insuringparallelism of the head and tail shafts of the conveyor with respect toeach other.

Each shaft bearing whose position is to be adjusted is supported on aslidably adjustable mounting means, and a fluid motor such as ahydraulic ram is mounted with the cylinder thereof in a fixed positionon the shaft support structure for a given range of adjustment of thebearing, the ram being pressurized to move the slidable mounting meansand the bearing carried thereby to an adjusted position. Preciselydimensioned shims are interposed between the cylinder of the hydraulicram and the adjustable mounting means to maintain the bearing in a givenadjusted position, and after the shims have been so interposed thehydraulic ram is depressurized but the ram cylinder remains in its fixedposition to serve as an abutment for the shims.

Further objects and advantages of the invention become apparent with thefollowing description taken in conjunction with the accompanyingdrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic view of a grateconveyor carrying a load of ore pellets or the like through a pluralityof heated zones prior to delivering the pellets to a rotary kiln or thelike;

FIG. 2 is a diagrammatic plan view of the grate conveyor of FIG. 1illustrating the rectangular outline defined by the bearings of the headshaft and of the tail shaft with respect to each other, with consequentparallelism of the head and tail shafts with respect to each other;

FIG. 3 is a view in side elevation showing the tail shaft bearing at oneside of the grate conveyor, together with the adjusting mechanismtherefor;

FIG. 3A is a perspective view of one of the shims of FIG. 3;

FIG. 4 is a view along line IV-IV of FIG. 3 of the beam or otherstructural member on which the tail shaft bearing and the adjustingdevice of FIG. 3 are supported;

FIG. 5 is an end view of FIG. 3 showing the slidable carriage whichsupports one end of the tail shaft for adjustable movement; and

FIG. 6 is a side elevation view on a larger scale of the hydraulicadjusting device of FIG. 3, together with the hydraulic pump used inassociation with the hydraulic adjusting device.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the view ofFIG. 1, there is shown a diagrammatical view of a Grate-Kiln systemgenerally indicated at 10 including a grate enclosure generallyindicated at 12 and a rotary kiln generally indicated at 14. Systems ofthis general type are shown, forexample, in US. Pat. Nos.2,925,336-Stowasser, 3,110,483Baxa, 3,'l l0,75lBade, and3,396,952-Jennrich et al. A grate conveyor generally indicated at 16passes around the head shaft 18 which is supported for rotation bysuitable oppositely disposed bearing 20, 20, and around a tail shaft 22which is supported for rotation by suitable oppositely disposed bearings24, 24'. The term hearing as used in this application is intended toinclude the actual bearing element and also the housing for the bearingelement. Oppositely disposed conveyor chains 26 are trained aroundsprockets 28 fixed on the head shaft 18, and around sprockets 30 fixedon the tail shaft 22. The head shaft 18 in the illustrated embodiment isrotatably driven by a suitable drive means 19, whereby to cause rotationof the conveyor 16. In the present embodiment, the tail shaft 22 rotatesin bearings 24, 24'. However, tail shaft 22 could be nonrotatable in itsbearings, with sprockets 30 being rotatable relative to the nonrotatabletail shaft 22. Suitable grates, not shown, are connected between andmovably carried by the oppositely disposed chains 26 in a manner wellknown in the art.

The conveyor 16 receives a load of green (i.e., untreated) mineral orepellets at the loading zone indicated at A at the right-hand side ofFIG. 1. The conveyor 16 moves from right to left with respect to theview of FIG. l, and carries the pellets successively through a firstdrying section indicated B, through a second drying section indicated atC, and through a preheat section indicated at D. The pellets in thevarious sections B, C and D are heated by exhaust gases from rotary kiln14 in a manner well known in the art. When the pellets reach the end ofthe upper run of the conveyor 16 at the left of the view of FIG. 1, theyare removed from the conveyor by a scraper 32 which delivers the pelletsby means of a chute or the like 34 to the inlet end of rotary kiln 14.The upper run of each conveyor chain 26 is supported by parallel rollermembers 36, and the lower run of each conveyor chain is supported byreturn rollers 38. Conveyor 16 including the chains 26 thereof, isheated to an elevated temperature such as, for example, 500Fahrenheitduring its passage through the grate enclosure 12.

Referring now to FIG. 3, there is shown the arrangement for tensioningconveyor chain 26, and hence the conveyor 16 supported by the conveyorchain, at one side of the conveyor structure, it being understood thatthe adjustment arrangement on the other side is exactly the same.Bearing 24 for tail shaft 22 is mounted on a base or mounting means 40which is slidably adjustably movable upon a beam 42 which, in turn, issuitably supported with respect to the ground or other foundation bysuitable vertical frame members 44 and 46.

Since head shaft 18 is connected to the drive means 19, it is simplerand preferable to adjust the chain tension by adjusting the position ofthe bearings 24, 24 of tail shaft 22.

The slidably adjustable base 40 upon which bearing 24 is mounted isprovided with a vertical abutment 41 which is engaged by shims 90, aswill be explained more fully hereinafter. Abutment 41 is also providedin the face thereof directed toward hydraulic ram 60 (to be described)with a shallow countersunk recess 43 which serves as a seat for the endof piston 64 of the hydraulic ram 60.

As best seen in FIGS. 3, 4 and 5, beam member 42 on which bearing 24 ismounted for sliding adjustment is in the form of a box beam including atop plate or wall member 50, a bottom plate or wall member 52, andoppositely disposed laterally spaced side walls 54. It will be noted inFIG. 5 that the top plate 50 projects laterally on either side of theoppositely disposed side walls 54, and that the slidably movable base 40for bearing 24 is provided with detachable keeper members 56 held inplace by bolts 57, which are adapted to underlie the under surface ofthe laterally projecting portions of top wall 50 of box beam 42, toprevent upward displacement of upward angular movement of the bearing24. However, sufficient clearance is provided between keepers 56 and theunder surface of wall 50 to permit linear movement of base 40 along beam42. As will be explained more fully hereinafter, adjustably movablebearing 24 is held in a given adjusted position by the cooperation of ahydraulic ram and shims.

In accordance with a feature of the construction, a fluid motor in theform of a hydraulic ram generally indicated at 60 is provided as apermanent part of the tail shaft position adjusting assembly. Thehydraulic ram 60 comprises a cylinder 62 and a hydraulically movablepiston member 64 which may move from a position in which it issubstantially completely retracted within cylinder 62 to a position inwhich it is advanced a predet'ermnied distance such as 12-rinches, forexample, beyond the end of cylinder 62. Cylinder 62 is provided with anelongated lug member 66 which is rigidly secured to cylinder 62 andwhich projects laterally downwardly from cylinder 62, as best seen inthe views of FIGS. 3 and 6. In order to receive lug member 66 ofhydraulic ram 60, the upper plate or wall 50 of the box beam 42 isprovided with several longitudinally spaced holes 68A and 68B of squareor rectangular crosssection as best seen in FIG. 4 through which lugmember 66 may extend down into the interior of hollow box beam 42. In atypical installation, the aperture or hole 68A or 68B is made, forexample, of a cross-sectional size of 7-95 by 646 inches and thecross-section of the lug 66 which is received in aperture 68A or 688 isjust sufficiently less than the size of the aperture 68A or 68B topermit easy insertion or removal of the lug relative to the aperture 68Aor 688 as the case may be.

A pair of lug stop blocks 80 and 82 are positioned within the hollowinterior of beam 42 in spaced relation to each other longitudinally ofbeam 42. The lug stop blocks 80 and 82 are rigidly secured, as bywelding, to the inside surface of bottom wall 52 of beam 42. Lug stopblock 82 is located in the example shown a distance such as 12% inchesto the right of lug stop block 80, as seen in the view of FIG. 3. Thefunction of lug stop blocks 80 and 82 is to absorb the force or thruston the lower end of lug 66 which might tend to cause counterclockwiseangular movement of ram 60 and the connected lug 66, relative to theview shown in FIG. 3. Lug stop block 80 is accurately positioned so asto engage the right-hand edge with respect to the view of FIG. 3 of lug66 when hydraulic ram 60 is in the Station 1 position shown in FIG. 3 inwhich lug 66 passes through hole 68A; while lug stop block 82 iscorrespondingly located to engage the right-hand edge of lug 66 when thehydraulic ram 60 has been moved to Station 2 in which lug 66 engages thefacing edge of lug stop block 82.

DESCRIPTION OF OPERATION Adjustment for Chain Length Increase AfterStarting from Cold Start Assume that grate conveyor 16 is being startedup after having been shut down so that the temperature of the grateconveyor at starting is substantially 500) Fahrenheit lower than it willbe after it reaches average operating temperature. For a cold start,hydraulic ram 60 is mounted on support beam 42 at the Station 1"position shown in FIG. 3 in which lug 66 carried by hydraulic ram 60 isreceived in aperture 68A of top wall 50 of beam 42, and in which thelower end of lug 66 abuts against the left-hand face of stop block 80.At the time of the cold start-up, piston 64 of hydraulic ram 60 is inits completely retracted position within cylinder 62, and slide carriage40 on which bearing 24 of tail shaft 22 is mounted is at the extremeleft position with respect to the view shown in FIG. 3 in which verticalabutment 41 of carriage 40 is engaged with end edge 63 of the cylinder62 of hydraulic ram 60. In the retracted positon of piston 64, the outerface 65 of piston 64 is substantially flush with the end edge 63 ofcylinder 62.

As conveyor chain 26 comes up to normal operating temperature which mayrepresent, for example, a rise of approximately 500 F. from its coldstart-up temperature, an elongation of the chain will occur, such as a12-inch length increase for a chain of 400 pitches having a total coldlength of 4,000 inches, in accordance with the example previously given.A total increase in length of 12 inches due to the temperature rise asjust explained is distributed, of course, on both the upper and lowerruns of the conveyor chain, and hence a movement to the right of 6inches with respect to the view of FIG. 3 of the tail shaft bearing 24will restore the chain to substantially the original tension which ithad when cold. In order to move tail shaft bearing 24 the 6 inchdistance as just described, a hydraulic pump 70 is connected by conduit72 and coupler 74 to inlet 76 of the hydraulic ram 60 and pump 70 isactuated to pump hydraulic fluid into cylinder 62 to cause piston 64 toadvance and move slidably movable carriage or mounting means 40 thenecessary distance, such as 6 inches, for example, required to retensionchain 26 to its original cold tension, plus an additional distance, suchas inch, for example, to provide sufficient clearance for the insertionof shims 90 to be described. It will be understood that the sameoperation is performed on each of the opposite bearings 24 and 24' ofFIG. 2, and that each bearing 24, 24 is moved by a correspondinghydraulic ram.

Pump 70 is provided internally thereof with its own self-containedreservoir for hydraulic fluid having a capacity sufficient to advancepiston 64 of the pump through the maximum desired stroke, such as 12-inches, for example.

When the piston 64 of the hydraulic ram has been advanced the desireddistance for the particular adjustment being made, say six and one-halfinches, for example, a plurality of the U-shaped shims 90 shown in FIG.3A are inserted in the space between the forward end 63 of the cylinder62 of hydraulic ram 60 and the facing surface of vertical abutment 41 onslidable carriage 40. Each of the shims 90 is precisely dimensioned tohave a predetermined thickness. For example, each shim 90 may have athickness of precisely 2 inches in a direction extending lengthwise ofbeam 42, so that if the hydraulic ram has advanced the slidable carriage40 a distance of 6 and /6 inches, for example, three of the shims 90will be positioned between end 63 of cylinder 62 and the facing surfaceof abutment 41 in the manner shown in FIG. 3. The U-shape of shims 90permits the shims to straddle piston rod 64 of hydraulic ram 60.

After shims 90 are in position as shown in FIG. 3, with the number ofshims multiplied by the thickness of each shim corresponding to thenecessary amount of shifting of tail shaft 22 to retension chain 26 toits orignal tension, valve 79 on pump 70 is then actuated to permitreverse flow of hydraulic fluid from cylinder 62 back to pump 70,permitting slidable carriage 40 under the influence of the forces on thechains such as the weight and tension on the chains, to move to the leftrelative to FIG. 3, to retract piston 64 to a position in which itexerts zero pressure on carriage 40 and in which the preciselydimensioned shims 90 will be tightly compressed between abutment 41 andthe end 63 of cylinder 62. The weight of the chains and connected gratesalone would normally be sufficient to move carriage 40 as justdescribed. In this condition in which shims 90 are in the tightlycompressed relation just described, the extra one-half inch clearancedistance to which carriage 41 has been advanced will have been removed,and the shaft 22 will have been advanced exactly 6 inches (in theassumed example) beyond its original cold start-up position. Since thesame operation as that just described is performed on each of theoppositely disposed tail shaft bearings 24, 24, it can be seen that therectangular relation of the head and tail shaft bearings (FIG. 2) andthe parallel relation of shafts 20, 22 is maintained.

With the hydraulic circuit between hydraulic .ram 60 and pump 70connected for reverse flow as just described, pump 70 may bedisconnected from hydraulic cylinder 62 when it is noted that the shims90 are tight, which is indicative that zero pressure is being exerted bypiston 64 on abutment 41 of carriage 40.

After the shims have been positioned as just described to make theadjustment for temperature elongation of chain, hydraulic ram 60 remainsin position on the structure as shown in the view of FIG. 3 and the endof the cylinder 62 serves as an abutment for the shims during thecontinuous operation of the grate conveyor. The retainer pin 84 is usedto secure the slidable carriage 40 to the box beam 42 only during thetransition period when hydraulic ram 60 is being moved from oneadjustment station to anotehr adjustment station, as from adjustmentstation No. l to adjustment station No. 2, as will be described.

ADJUSTMENT TO RETENSION CHAIN TO COMPENSATE FOR WEAR ON CHAIN Assumethat at the end of a predetermined period of operation, say threemonths, for example, it is visually observed that chain 26 has becomeloose due to wear on the chain as previously explained. The chain hasalready been retensioned for the change in length due to the temperaturerise to operating temperature as previously explained and at the end ofthe three month period just assumed, the depressurized hydraulic ram 60is in position on beam 42 and serves as an abutment as previouslyexplained with three shims in position between cylinder 62 of thehydraulic ram and the abutment 41 on bearing slide carriage 40. In orderto now further tension the chain to compensate for wear at the end ofthe assumed 3 month period of operation, pump is again connected tohydraulic cylinder 62 and hydraulic fluid is pumped by the pump into thehydraulic cylinder to cause piston 64 to advance bearing 24 thenecessary distance to retension chain 26 to the desired optimum tensionwhich, it is assumed, for sake of example, to be another 6 inches, plusan additional distance such as one-half inch to provide clearance forthe insertion of the additional shims required. When bearing 24 has beenadvanced the additional 6 inches plus clearance distance for a totaladvance of 12 inches plus clearance distance (including the prioradvance of 6 inches for temperature compensation), three additionalshims are added to the three already in place for a total of 6 shimsbetween the end of the hydraulic 62 and the facing surface of theabutment 41 on carriage 40. Thus, shaft 22 will have been advanced atotal of 12 inches (plus clearance for shim insertion) 6 inches of whichwere for temperature compensation and 6 inches of which were for wearcompensation. With the 6 2-inch thick shims in position, hydraulicpressure is again removed from piston 64 by opening pump valve 79 whichpermits reverse flow of hydraulic fluid from cylinder 62 back to pump70. The forces on chain 26 cause movement of slidable carriage 40 totake up the clearance provided for shim insertion, and the shims packbecomes tightly compressed, all as previously explained. Pump 70 is thendisconnected. Hydraulic ram 60 remains in the position shown in FIG. 3in which end wall 63 of cylinder 62 serves as an abutment whichcooperates with shims to hold slidable carriage 40 in the new positionto which it has been adjusted.

Now assume that at the end of 6 months of operation the wear on chain 26has again caused sufficient looseness that it is desirable to againretension the chain. The hydraulic ram in the Station 1 position shownin FIG. 3 has been moved to its extreme limit of adjustment, since it isassumed that piston 64 has only a range of movement of 12 inches plus anadditional amount such as one-half inch required to provide clearancefor shim insertion. It is now necessary if any further adjustment is tobe made, to reposition the hydraulic ram at another adjusting stationalong beam 42.

To facilitate removal of the hydraulic ram 60 from adjustment Station 1preparatory to positioning it at adjustment Station 2, pump 70 isreconnected to the hydraulic ram and sufficient hydraulic fluid isadmitted to advance the bearing carriage 40 through a clearance distancesufficient to loosen the shim pack. Retainer pin 84 is dropped throughaligned apertures 85 and 86 in slidable carriage 40 and in the upperplate 50 of box beam 42 to temporarily hold slidable carriage 40 and thebearing 24 carried thereby in the newly adjusted position just mentionedat which the shims 90 are sufficiently loose to permit easy removalthereof. To remove the hydraulic piston 60 and the shims from thestation 1 position shown in FIG. 3, the hydraulic ram is thendepressurized by opening valve 79 and the depressurized piston 64 may bemanually retracted. Pump 70 is then disconnected from the hydraulic ram.Hydraulic ram 60 is then removed from its engagement with aperture 68A(Station 1) and is repositioned into the next adjustment station(Station 2) in which lug 66 engages hole or aperture 68B in plate 50 ofbox beam 42, with the right-hand edge of lug 66 engaging the lefthandedge, with respect to the view of FIG. 3, of lug stop block 82, and withthe surface 63 of cylinder 62 engaging abutment 41 on carriage 40. Withhydraulic ram 60 in position at Station 2 as just described, retainerpin 84 is removed from engagement with the aperture 86 in upper plate 50of box beam 42.

With hydraulic ram 60 at the second adjustment station as just describedin which lug 66 engages aperture 68B of box beam 42, another additionaltwelve inches of adjustment is available in addition to the adjustmentwhich has already been made at adjustment Station No. 1. The adjustmentof the position of bearing 24 at adjustment Station No. 2 is made in thesame manner as described in connection with Station No. 1.

It will be understood that the tail shaft adjusting apparatus andstructure described is duplicated on each of opposite sides of theconveyor for each of the re spective adjustably movable tail shaftbearings 24 and 24', and that when any adjustment is made for one tailshaft bearing, a corresponding adjustment is made for the opposite tailshaft bearing.

It might be noted that in a typical installation of the type describedhereinbefore and shown in the drawings, each tail shaft bearing 24, 24may be subjected to a resultant force of the order of magnitude of200,000 pounds per bearing, this force being a resultant of the variousforces to which the bearing is subjected.

While only two adjustment stations have been shown in the illustratedembodiment, obviously additional adjustment stations could be providedif it is contemplated that the particular grate conveyor installationwill require adjusting movement of tail shaft 22 beyond that provided bythe two adjustment stations shown in the illustrated embodiment.

When it is desired to shut down the conveyor which has been tensioned inthe manner previously described, in order to avoid unduly stressing thechains whose temperature is dropping with resultant contraction in chainlength, a procedure which is substantially the reverse of that describedis followed to compensate for the decreasing length of the chains. Shimsare removed as necessary, and the hydraulic ram may be transferred fromone adjustment station to another, if necessary to compensate for thedecreased chain length during the cooling-off period of the grateconveyor.

All of the various adjustments mentioned hereinbefore may be made whilethe conveyor is in operation. Although the conveyor and conveyor chainare operating at a high temperature, the ambient temperature at thelocation where the adjustments are being made is much lower than that ofthe conveyor and conveyor chains, and is sufficiently low to permitaccess by workmen making the adjustments.

By using a plurality of adjustment stations as shown and described inthe present application, a smaller and shorter ram may be used in agiven installation than if the ram were to be left at a singleadjustment station, since use of a single adjustment station wouldrequire a longer ram having a piston with a longer stroke with resultantgreater stresses, than in the embodiment described in the presentapplication.

From the foregoing detailed description of the present invention, it hasbeen shown how the objects of the invention have been obtained in apreferred manner. However, modifications and equivalents of thedisclosed concepts such as readily occur to those skilled in the art areintended to be included within the scope of this invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a conveyor system including a head shaft and a tail shaft, aconveyor chain trained around said head shaft and said tail shaft, afirst pair of laterally spaced bearings supporting said head shaft, asecond pair of laterally spaced bearings supporting said tail shaft, theimprovement which comprises supporting each bearing of one of said pairson a separate slidable mounting means whereby to permit adjustment ofthe location of the shaft supported by said one of said pairs ofbearings to permit tensioning of said chain, a fluid motor correspondingto each slidable mounting means, each of said fluid motors including acylinder and a piston linearly movable in said cylinder, means foranchoring the cylinder of each fluid motor in a fixed position relativeto a stationary support comprising a lug member affixed to therespective cylinder, said lug member being adapted to detachably engagean aperture in a corresponding stationary support member, eachrespective piston being engageable with a corresponding one of saidslidable mounting means, whereby to slidably adjust the position of saidcorresponding mounting means, and precisely dimensioned shim meansextending throughout the space between the corresponding mounting meansand the cylinder of the corresponding fluid motor, whereby to hold eachrespective mounting means in a given adjusted position.

2. A conveyor system as defined in claim 1 in which the bearings of saidone of said pairs support said tail shaft.

3. A conveyor system as defined in claim 1 in which said shim 'meansbetween each respective mounting meanS and the corresponding cylinder isadapted to straddle the corresponding piston.

4. A conveyor system as defined in claim 1 in which each respectivestationary support member comprises a box beam contiguous a lateral sideof said conveyor for supporting a corresponding bearing of said one ofsaid pairs, the slidable mounting means for supporting each respectivebearing being mounted for slidable movement along the upper wall of thecorresponding box beam, said upper wall being provided with an apertureto receive said lug member whereby said lug member extends into theinterior of said box beam, and a stop block mounted on the interior ofsaid box beam and engageable with said lug member to absorb forces onsaid lug member.

5. In a grate conveyor system including a head shaft and a tail shaft, aconveyor chain trained around said head shaft and said tail shaft, aplurality of grate members connected to and movable with said chain, abearing supporting said head shaft, a bearing supporting said tailshaft, the improvement which comprises mounting one of said bearings ona slidably movable mounting means whereby to permit adjustment of thelocation of the corresponding shaft to permit tensioning of said chain,a fluid operated motor associated with said mounting means, said motorincluding a cylinder and a piston linearly movable in said cylinder,means for anchoring the cylinder of said fluid motor in a fixed positionrelative to a stationary support, comprising a lug member affixed tosaid cylinder, said lug member being adapted to engage an aperture insaid stationary support, said piston being engageable with said mountingmeans whereby to slidably adjust the position of said mounting means,and precisely dimensioned shim means extending throughout the spacebetween said mounting means and said cylinder, whereby to hold saidmounting means in a given adjusted position.

6. A grate conveyor system as defined in claim in which said stationarysupport comprises a box beam contiguous a lateral side of said conveyorfor supporting said one bearing, the slidable mounting means for saidone bearing being mounted for slidable movement along the upper wall ofsaid box beam, said upper wall being provided with an aperture toreceive said lug member whereby said lug member extends into theinterior of said box beam, and a stop block mounted on the interior ofsaid box beam and engageable with said lug member to absorb forces onsaid lug member.

7. In a grate conveyor system including a head shaft and a tail shaft, aconveyor chain trained around said head shaft and said tail shaft, aplurality of grate members connected to and movable with said chain, abearing supporting said head shaft, a bearing supporting said tailshaft, the improvement which comprises mounting one of said bearings ona slidably movable mounting means whereby to permit adjustment of thelocation of the corresponding shaft to permit tensioning of said chain,a fluid operated motor associated with said mounting means, said motorincluding a cylinder and a piston linearly movable in said cylinder,said piston being engageable with said mounting means whereby toslidably adjust the position of said mounting means, preciselydimensioned shim means extending throughout the space between saidmounting means and said cylinder, whereby to hold said mounting means ina given adjusted position, and cooperating means carried by saidcylinder and by a stationary sup port for selectively detachablyanchoring the cylinder of said fluid motor at any one of a plurality offixed positions along said stationary support whereby to provide aplurality of adjustment stations for adjustment of the location of saidcorresponding shaft.

8. A grate conveyor system as defined in claim 7 in which said onebearing supports said tail shaft.

9. A grate conveyor system as defined in claim 7 in which said shimmeans is adapted to straddle said piston.

10. In a grate conveyor system including a head shaft and a tail shaft,a conveyor chain trained around said head shaft and said tail shaft, aplurality of grate members connected to and movable with said chain, abearing supporting said head shaft, a bearing supporting said tailshaft, the improvement which comprises mounting one of said bearings ona slidably movable mounting means whereby to permit adjustment of thelocation of the corresponding shaft to permit tensioning adjustment ofsaid chain, motor means associated with said mounting means, said motormeans including a housing and a linearly movable ram element, means foranchoring said housing at a fixed position relative to a stationarysupport, comprising a lug member affixed to said housing, said lugmember being adapted to detachably engage an aperture in said stationarysupport, said ram element being engageable with said mounting meanswhereby to slidably adjust the position of said mounting means, andprecisely dimensioned shim means extending throughout the space betweensaid mounting means and said housing, whereby to hold said mountingmeans in an adjusted position to which it has been moved.

11. A grate conveyor system as defined in claim 10 in which saidstationary support comprises a box beam contiguous a lateral side ofsaid conveyor for supporting said one bearing, the slidable mountingmeans for said one bearing being mounted for slidable movement along theupper wall of said box beam, said upper wall being provided with anaperture to receive said lug member whereby said lug member extends intothe interior of said box beam, and a stop block mounted on the interiorof said box beam and engageable with said lug member to absorb forces onsaid lug member.

12. A grate conveyor system as defined in claim 10 in which said shimmeans is adapted to straddle said ram element.

13. A grate conveyor system as defined in claim 10 in which said onebearing supports said tail shaft.

14. In a grate conveyor system including a head shaft and a tail shaft,a conveyor chain trained around said head shaft and said tail shaft, aplurality of grate members connected to and movable with said chain, abearing supporting said head shaft, a bearing supporting said tailshaft, the improvement which comprises mounting one of said bearings ona slidable movable mounting means whereby to permit adjustment of thelocation of the corresponding shaft to permit tensioning adjustment ofsaid chain, motor means associated with said mounting means, said motormeans including a housing and a linearly movable ram element, said ramelement being engageable with said mounting means whereby to slidablyadjust the position of said mounting means, precisely dimensioned shimmeans extending throughout the space between said mounting means andsaid housing, whereby to hold said mounting means in an adjustedposition to which it has been moved, and cooperating means carried bysaid housing and by a stationary support for selectively detachablyanchoring the housing of said motor means at any one of a plurality offixed positions along said stationary support whereby to provide aplurality of adjustment stations for adjustment of the location of saidcorresponding shaft.

15. In a conveyor system including a head shaft and a tail shaft, aconveyor trained around said head shaft and said tail shaft, a bearingsupporting said head shaft, a bearing supporting said tail shaft, theimprovement which comprises mounting one of said bearings on a slidablymovable mounting means whereby to permit adjustment of the location ofthe corresponding shaft to permit tensioning adjustment of saidconveyor, motor means associated with said mounting means, said motormeans including a housing and a linearly movable ram element, means foranchoring said housing at a fixed position relative to a stationarysupport, comprising a lug member affixed to said housing, said lugmember being adapted to detachably engage an aperture in said stationarysupport, said ram element being engageable with said mounting meanswhereby to slidably adjust the position of said mounting means, thespace between said mounting means and said housing being adapted toreceive precisely dimensioned shim means whereby to hold said mountingmeans in an adjusted position to which it has been moved.

16. A conveyor system as defined in claim 15 in which said stationarysupport comprises a box beam contiguous a lateral side of said conveyorfor supporting said one bearing, the slidable mounting means for saidone bearing being mounted for slidable movement along the upper wall ofsaid box beam, said upper wall being provided with an aperture toreceive said lug member whereby said lug member extends into theinterior of said box beam, and a stop block mounted on the interior ofsaid box beam and engageable with said lug member to absorb forces onsaid lug member.

17. In a conveyor system as defined in claim 15, precisely dimensionedshim means interposed in the space between said mounting means and saidhousing.

18. In a conveyor system including a head shaft and a tail shaft, aconveyor trained around said head shaft and said tail shaft, a bearingsupporting said head shaft, a bearing supporting said tail shaft, theimprovement which comprises mounting one of said bearings on a slidablymovable mounting means whereby to permit adjustment of the location ofthe corresponding shaft to permit tensioning adjustment of saidconveyor, motor means associated with said mounting means, said motormeans including a housing and a linearly movable ram element, said ramelement being engageable with said mounting means whereby to slidablyadjust the position of said mounting means, the space between saidmounting means and said housing being adapted to receive preciselydimensioned shim means whereby to hold said mounting means in anadjusted position to which it has been moved, and cooperating meanscarried by said housing and by a stationary support for selectivelydetachably anchoring the housing of said motor means at any one of aplurality of fixed positions along said stationary support whereby toprovide a plurality of adjustment stations for adjustment of thelocation of said corresponding shaft.

19. In a conveyor system as defined in claim 18, precisely dimensionedshim means interposed in the space between said mounting means and saidhousing.

20. In a conveyor system as defined in claim 18, said linearly movableram element including a free end facing said mounting means, said freeend being engageable with said mounting means but not connected to saidmounting means.

1. In a conveyor system including a head shaft and a tail shaft, aconveyor chain trained around said head shaft and said tail shaft, afirst pair of laterally spaced bearings supporting said head shaft, asecond pair of laterally spaced bearings supporting said tail shaft, theimprovement which comprises supporting each bearing of one of said pairson a separate slidable mounting means whereby to permit adjustment ofthe location of the shaft supported by said one of said pairs ofbearings to permit tensioning of said chain, a fluid motor correspondingto each slidable mounting means, each of said fluid motors including acylinder and a piston linearly movable in said cylinder, means foranchoring the cylinder of each fluid motor in a fixed position relativeto a stationary support comprising a lug member affixed to therespective cylinder, said lug member being adapted to detachably engagean aperture in a corresponding stationary support member, eachrespective piston being engageable with a corresponding one of saidslidable mounting means, whereby to slidably adjust the position of saidcorresponding mounting means, and precisely dimensioned shim meansextending throughout the space between the corresponding mounting meansand the cylinder of the corresponding fluid motor, whereby to hold eachrespective mounting means in a given adjusted position.
 2. A conveyorsystem as defined in claIm 1 in which the bearings of said one of saidpairs support said tail shaft.
 3. A conveyor system as defined in claim1 in which said shim means between each respective mounting meanS andthe corresponding cylinder is adapted to straddle the correspondingpiston.
 4. A conveyor system as defined in claim 1 in which eachrespective stationary support member comprises a box beam contiguous alateral side of said conveyor for supporting a corresponding bearing ofsaid one of said pairs, the slidable mounting means for supporting eachrespective bearing being mounted for slidable movement along the upperwall of the corresponding box beam, said upper wall being provided withan aperture to receive said lug member whereby said lug member extendsinto the interior of said box beam, and a stop block mounted on theinterior of said box beam and engageable with said lug member to absorbforces on said lug member.
 5. In a grate conveyor system including ahead shaft and a tail shaft, a conveyor chain trained around said headshaft and said tail shaft, a plurality of grate members connected to andmovable with said chain, a bearing supporting said head shaft, a bearingsupporting said tail shaft, the improvement which comprises mounting oneof said bearings on a slidably movable mounting means whereby to permitadjustment of the location of the corresponding shaft to permittensioning of said chain, a fluid operated motor associated with saidmounting means, said motor including a cylinder and a piston linearlymovable in said cylinder, means for anchoring the cylinder of said fluidmotor in a fixed position relative to a stationary support, comprising alug member affixed to said cylinder, said lug member being adapted toengage an aperture in said stationary support, said piston beingengageable with said mounting means whereby to slidably adjust theposition of said mounting means, and precisely dimensioned shim meansextending throughout the space between said mounting means and saidcylinder, whereby to hold said mounting means in a given adjustedposition.
 6. A grate conveyor system as defined in claim 5 in which saidstationary support comprises a box beam contiguous a lateral side ofsaid conveyor for supporting said one bearing, the slidable mountingmeans for said one bearing being mounted for slidable movement along theupper wall of said box beam, said upper wall being provided with anaperture to receive said lug member whereby said lug member extends intothe interior of said box beam, and a stop block mounted on the interiorof said box beam and engageable with said lug member to absorb forces onsaid lug member.
 7. In a grate conveyor system including a head shaftand a tail shaft, a conveyor chain trained around said head shaft andsaid tail shaft, a plurality of grate members connected to and movablewith said chain, a bearing supporting said head shaft, a bearingsupporting said tail shaft, the improvement which comprises mounting oneof said bearings on a slidably movable mounting means whereby to permitadjustment of the location of the corresponding shaft to permittensioning of said chain, a fluid operated motor associated with saidmounting means, said motor including a cylinder and a piston linearlymovable in said cylinder, said piston being engageable with saidmounting means whereby to slidably adjust the position of said mountingmeans, precisely dimensioned shim means extending throughout the spacebetween said mounting means and said cylinder, whereby to hold saidmounting means in a given adjusted position, and cooperating meanscarried by said cylinder and by a stationary support for selectivelydetachably anchoring the cylinder of said fluid motor at any one of aplurality of fixed positions along said stationary support whereby toprovide a plurality of adjustment stations for adjustment of thelocation of said corresponding shaft.
 8. A grate conveyor system asdefined in claim 7 in which said one bearing supports said tail shaft.9. A grate conveyor system as defined in claim 7 in which said shimmeans is adapted to straddle said piston.
 10. In a grate conveyor systemincluding a head shaft and a tail shaft, a conveyor chain trained aroundsaid head shaft and said tail shaft, a plurality of grate membersconnected to and movable with said chain, a bearing supporting said headshaft, a bearing supporting said tail shaft, the improvement whichcomprises mounting one of said bearings on a slidably movable mountingmeans whereby to permit adjustment of the location of the correspondingshaft to permit tensioning adjustment of said chain, motor meansassociated with said mounting means, said motor means including ahousing and a linearly movable ram element, means for anchoring saidhousing at a fixed position relative to a stationary support, comprisinga lug member affixed to said housing, said lug member being adapted todetachably engage an aperture in said stationary support, said ramelement being engageable with said mounting means whereby to slidablyadjust the position of said mounting means, and precisely dimensionedshim means extending throughout the space between said mounting meansand said housing, whereby to hold said mounting means in an adjustedposition to which it has been moved.
 11. A grate conveyor system asdefined in claim 10 in which said stationary support comprises a boxbeam contiguous a lateral side of said conveyor for supporting said onebearing, the slidable mounting means for said one bearing being mountedfor slidable movement along the upper wall of said box beam, said upperwall being provided with an aperture to receive said lug member wherebysaid lug member extends into the interior of said box beam, and a stopblock mounted on the interior of said box beam and engageable with saidlug member to absorb forces on said lug member.
 12. A grate conveyorsystem as defined in claim 10 in which said shim means is adapted tostraddle said ram element.
 13. A grate conveyor system as defined inclaim 10 in which said one bearing supports said tail shaft.
 14. In agrate conveyor system including a head shaft and a tail shaft, aconveyor chain trained around said head shaft and said tail shaft, aplurality of grate members connected to and movable with said chain, abearing supporting said head shaft, a bearing supporting said tailshaft, the improvement which comprises mounting one of said bearings ona slidable movable mounting means whereby to permit adjustment of thelocation of the corresponding shaft to permit tensioning adjustment ofsaid chain, motor means associated with said mounting means, said motormeans including a housing and a linearly movable ram element, said ramelement being engageable with said mounting means whereby to slidablyadjust the position of said mounting means, precisely dimensioned shimmeans extending throughout the space between said mounting means andsaid housing, whereby to hold said mounting means in an adjustedposition to which it has been moved, and cooperating means carried bysaid housing and by a stationary support for selectively detachablyanchoring the housing of said motor means at any one of a plurality offixed positions along said stationary support whereby to provide aplurality of adjustment stations for adjustment of the location of saidcorresponding shaft.
 15. In a conveyor system including a head shaft anda tail shaft, a conveyor trained around said head shaft and said tailshaft, a bearing supporting said head shaft, a bearing supporting saidtail shaft, the improvement which comprises mounting one of saidbearings on a slidably movable mounting means whereby to permitadjustment of the location of the corresponding shaft to permittensioning adjustment of said conveyor, motor means associated with saidmounting means, said motor means including a housing and a linearlymovable ram element, means for anchoring said housing at a fixedposition relative to a stationary support, comprising a lug memberaffixEd to said housing, said lug member being adapted to detachablyengage an aperture in said stationary support, said ram element beingengageable with said mounting means whereby to slidably adjust theposition of said mounting means, the space between said mounting meansand said housing being adapted to receive precisely dimensioned shimmeans whereby to hold said mounting means in an adjusted position towhich it has been moved.
 16. A conveyor system as defined in claim 15 inwhich said stationary support comprises a box beam contiguous a lateralside of said conveyor for supporting said one bearing, the slidablemounting means for said one bearing being mounted for slidable movementalong the upper wall of said box beam, said upper wall being providedwith an aperture to receive said lug member whereby said lug memberextends into the interior of said box beam, and a stop block mounted onthe interior of said box beam and engageable with said lug member toabsorb forces on said lug member.
 17. In a conveyor system as defined inclaim 15, precisely dimensioned shim means interposed in the spacebetween said mounting means and said housing.
 18. In a conveyor systemincluding a head shaft and a tail shaft, a conveyor trained around saidhead shaft and said tail shaft, a bearing supporting said head shaft, abearing supporting said tail shaft, the improvement which comprisesmounting one of said bearings on a slidably movable mounting meanswhereby to permit adjustment of the location of the corresponding shaftto permit tensioning adjustment of said conveyor, motor means associatedwith said mounting means, said motor means including a housing and alinearly movable ram element, said ram element being engageable withsaid mounting means whereby to slidably adjust the position of saidmounting means, the space between said mounting means and said housingbeing adapted to receive precisely dimensioned shim means whereby tohold said mounting means in an adjusted position to which it has beenmoved, and cooperating means carried by said housing and by a stationarysupport for selectively detachably anchoring the housing of said motormeans at any one of a plurality of fixed positions along said stationarysupport whereby to provide a plurality of adjustment stations foradjustment of the location of said corresponding shaft.
 19. In aconveyor system as defined in claim 18, precisely dimensioned shim meansinterposed in the space between said mounting means and said housing.20. In a conveyor system as defined in claim 18, said linearly movableram element including a free end facing said mounting means, said freeend being engageable with said mounting means but not connected to saidmounting means.